LITTLE ROCK, Ark. (AP) - Sen. Mark Pryor, the lone Democrat in Arkansas' congressional delegation, said Wednesday he remains opposed to gay marriage, even as Democratic senators from other conservative states have joined the growing chorus of lawmakers who support it.

"I oppose same-sex marriage, and I've been very clear about that and been that way for a long time," Pryor told reporters during a conference call Wednesday.

Pryor's stance makes him one of only three Democrats in the Senate who have not expressed support for gay marriage. The other two are Mary Landrieu of Louisiana and Joe Manchin of West Virginia.

Democratic Sens. Joe Donnelly of Indiana, Heidi Heitkamp of North Dakota, and Tim Johnson of South Dakota all have voiced support for gay marriage in the past week.

As for Republicans, Sens. Mark Kirk of Illinois and Rob Portman of Ohio both have announced their support for gay marriage.

Pryor's opposition to gay marriage is far from surprising in Arkansas, where none of the state's top Democrats - including Gov. Mike Beebe - have flipped on the issue. About three-quarters of voters in 2004 backed an amendment to the state's constitution to define marriage as between a man and a woman.

Republicans have targeted Pryor as he seeks re-election next year, with national conservative groups already airing television ads against the two-term lawmaker. No Republican has announced a bid yet to challenge Pryor.

When Pryor kicked off his re-election campaign last month, even his choice of former President Bill Clinton, who remains popular in his home state of Arkansas, as the headliner for his fundraiser proved problematic. Republicans were quick to question Clinton's announcement that he now opposes a law he signed in 1996 that bars federal recognition of same-sex marriages. Pryor said he disagrees and believes the Defense of Marriage Act is constitutional.

Pryor has other reasons to worry ahead of the 2014 election. Democrats have steadily declined in Arkansas, hampered by President Barack Obama's unpopularity in the state and Republicans' consolidation of power across the South.

Of the two other Democratic senators who haven't expressed support for gay marriage, Landrieu faces a challenge next year as Republican U.S. Rep. Bill Cassidy seeks to oust the third-term Democratic senator from her seat. Manchin isn't up for re-election until 2018.